
If there is a novel for it can you tell me where to read it and what chapter is it in the novel

If chapter 23 in manhwa, probably in chapter 77 in novel.
https://www.novelupdates.com/series/refusing-your-ex-husbands-obsession-a-guide/?pg=6#myTable

The art style is pretty but why does it has to become straight isn't he original a gay guy how did he turn to straight ╥﹏╥

Note that the blonde is craving for affection so when the fl said she loved him, his heart already set to not let go of that. It's not a matter of gay or bisexual but individual who shows him affection first. And for the step brother, it was said that he's obsessed and possessive so when the fl said she wanted to leave him, he doesn't like it cuz in his mind the fl would always be obsessed with him and not go for another so yeah...lol

it only gonna get worse so be prepared pookies(≧∀≦)

Haeyoung서 disfigured haewon해원 with boiling water on parts of his body also many other things and abuses him continuously later haewon dyes his hair black and due to all the scars he has from the abuse he endured takyeom basically abandons him and says he's too disgusting to have sex with (because of how he looks after everything) haeyoung compared haewon to one of his college friends who looks similar to haewon (but has money and more stable life) this makes haewon feel insecure and feel as if haeyoung likes the new guy better and he's being replaced (remember he's been so emotionally damaged at this point), inevitably haewon throws himself off the cliff in a suicide attempt and narrowly survives but has amnesia haeyoung has a lot of guilt and regrets all he's done and realizes how horrible he treated haewon and begins acting how he did before (normal) they start dating, eventually haewon gets his memory back. The end.

So that means Haewon ends up with that mf even after he got his memory back? Come on
I hoped for a better ending, like, a new guy would come into his life and rescue him, or he successfully kills himself and those mf loose their appetite, or gain courage and kill those 03.
I'm disappointed!!
Btw Thanks for the comment. I'm gonna drop this. Don't want to see how Haewon ends up with the worst mf.

I'm curious why people still can expect that way like expecting MC to find a new guy for a toxic story. You know, if the story is toxic from beginning then there's 99% chance that the endgame ML is also the toxic one. And suicide is also one of topic that can trigger some people, so I'm glad this story didn't end that way.
There's also more plot:
*SPOILER*
When he jumping off cliff, most people thought he was dead, and those 3 was losing their minds especially Haeyoung he often got hallucinations during that time. And Haewon is temporary losing memory not because of jumping off cliff but depression, so Haeyoung take him to get treatment for healing. At least Haeyoung treat him better in the end and stop abusing him.
My guy is bad at using money